120v Power Source for Car





Introduction: 120v Power Source for Car

I had purchased a tablet that I wanted to be able to charge in the car, but was unable to find a suitable car charger that would work with it. I then wanted to use a power inverter to charge it, but they are all big and bulky. I then had the idea to add a 120v power outlet to my console. I had a little change holder in front of my shifter that did nothing except collect trash. So, I modded it to house a 120v power outlet.

Step 1: Find a Suitible Place for Your Outlet.

Find somewhere that is convenient and not needed to place your outlet. The change holder popped right out and just barely fit the power outlet. I took the outlet cover and cut it down to follow the contour of the change holder. I then painted it black to match the interior. I then took a 120v electrical plug and wired it to the back of the outlet. Basically, now you have a 120v wall outlet with a extension cord on it. You could also just take a extension cord and cut one end off and wire it up the same way. I just happened to have some spare electrical wire and plugs laying around.

Step 2: Find a Suitable Power Inverter

I already purchased this one a while ago. It was small enough to hide under the center console. I plugged it into the wall outlet and then connected it to a 12v extension cord. I have a power outlet I never used in the ash tray. I was able to route the 12v extension to it from under the console and plug it in and have the ash tray closed so I never see the wires. You now have a working wall outlet in your car.

Step 3: Optional Step: Add Relay

The power outlet in my ash tray did not cut off when the vehicle was off. I purchased a 12v accessory relay from the local auto parts store and wired it inline with the 12v extension. Then i found a accessory power line that I could tap into and wired it to the relay. This way, I don't have to worry about unplugging the power inverter since it will now be controlled by the relay.

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    20 Discussions

    Having been a Master Electronics Tech and Electrician for 40+ years, who at one point designed and built emergency vehicle and class A RV AC/DC electrical systems containing 120/240 volt inverters & generators. I would not recommend this type of alteration for 2 reasons.

    1. 120VAC kills, even at low wattage, well within the ability of even the smallest automotive inverter. There is a reason mobile class inverters are completely metal encased and grounded, with special armored wiring used when receptacles are remote from the inverter, with even the receptacle fully metal encased and grounded.

    2. Inverters draw a LOT of current, especially at start up, and can easily overwhelm and damage the factory alternator/charging system. And, most modern systems are designed to output just enough for the vehicle with very little "Headroom" for accessories. EVERY system I designed and installed required an upgraded alternator and charging system modifications to aleviate damage to the factory system.

    2 replies

    I was going to comment on these very things, but you did it for me... In addition to your first point, the fact that this receptacle is facing upwards and below the pull out cup holder drawer leads to a high(ish) probability of debris falling into it. That would obviously be a bad thing.

    May want to put a GFC on it, spill a cup a water....

    1 reply

    Theoretically, the inverter should be fused from the 12V source... so GCFI would be somewhat (pointlessly) redundant. Although, with this setup, I can only imagine how difficulty it must be to actually change said fuse without screwing up the outlet covering.

    I'm using a very low powered inverter. Only around 60 watts. It came in handy when I needed to charge up a small video camera that only had a wall adapter. I only use it once in a while. I mainly put the relay in just in case I forget to unplug it. I only plug it up when I use it so it doesn't put a drain on the electrical system.

    But most electronicslike tablets and phones use very low DC voltages, Most chargers use transformers to convert the 120/240 AC to DC and convert it to 3, 5 or even 12 volts. Of course your tablet might be something else, but it is much better to get a car charger suitable for your tablet. But i do understand the need to have a 120/240v outlet in your car for some appliances...

    It seems a bit crazy (and wasteful) to step 12V up to 120VAC then convert it back down to 5V to charge your tablet! Suitable buck switching power supplies to convert automotive battery voltage down to 5V at 2A or more are available very cheaply on eBay, although it would be wise to protect them against load dump (see Wikipedia). Then you could put a nice little USB charging port on your car instead.

    You should investigate the signalling method used by the charger to tell the tablet how much current it can supply. This is normally done by resistors on the D+ and D- lines of the USB connector. See the section on "Charging ports" in the USB article on Wikipedia.

    This is great but you should note this is ONLY for very low power usage. Somebody might be tempted to plug in a high demand electrical appliance and let some of the magic smoke out of that tiny inverter.

    I personally would not recommend this.You may end up buying an alternator and/or a "computer" for you car. I tried this a few years ago on 2 separate vehicles. A 2000 Chevy and '06 Kia. Both cost me a chunk of $$ for repairs before I learned my lesson. There is a reason your vehicle didn't come with these outlets already. The electrical systems of most cars were not designed with this in mind. When
    current flows back into a voltage source, which is quite possible/probable, its voltage output suddenly
    increases. Imagine what this can do to sensitive electronic equipment...

    Looks great! I too would worry about spilling something or dropping something to get stuck since it's horizontal and in a heavily trafficked area.

    I will see if I can upload instructions in a few days. I actually did this mod to my car a few years ago. Just never had the chance to publish it.

    This is seriously awesome! Every car should come with an outlet already installed. I think if I did this, I would add one of those outlets that also has a couple usb ports in it. I wish you had a little more detail about how you did the wiring though. Unless you already know a fair bit about a car's wiring, the average person reading this probably wouldn't be able to follow these instructions to make their own. Finding an accessory line to tap into isn't for everyone.

    1 reply

    Never thought about the usb port. The inverter I have has a usb port charger on it. That may be my next upgrade. As far as the accessory line to tap into, you can get a fuse tap and attach it to the radio fuse and connect that to the relay. I will try to put up some sort of wiring diagram.